Spar—Any long piece of wood or other material.
Spar, Main—A spar within a surface and to which all the ribs are attached, such spar being the one situated nearest to the centre of pressure. It transfers more than half the lift from the ribs to the bracing.
Spar, Rear—A spar within a surface, and to which all the ribs are attached, such spar being situated at the rear of the centre of pressure and at a greater distance from it than is the main spar. It transfers less than half of the lift from the ribs to the bracing.
Strut—Any wooden member intended to take merely the stress of direct compression.
Strut, Interplane—A strut holding the top and bottom surfaces apart.
Strut, Fuselage—A strut holding the fuselage longerons apart. It should be stated whether top, bottom, or side. If side, then it should be stated whether right or left hand. Montant.
Strut, Extension—A strut supporting an “extension” when not in flight. It may also prevent the extension from collapsing upwards during flight.
Strut, Undercarriage—
Strut, Dope—A strut within a surface, so placed as to prevent the tension of the doped fabric from distorting the framework.
Serving—To bind round with wire, cord, or similar material. Usually used in connection with wood joints and wire cable splices.